Acoustical wall covering



June 23, 1936. c. K. ROOS ET AL 2,045,313

ACOUSTICAL WALL COVERING Filed Oct. 4, 1955 u i aye 2 07 9 f- Patented June 23, 1936 UNITED STATES PATENT OFFICE ACOUSTICAL WALL COVERING Chicago,

and George D. King,

sum Company, Chicago, 111., a corporation of Illinois Application October 4, 1933, Serial No. 692,078

16 Claims.

This invention relates to improvements in acoustical construction and has particular relation to acoustical coverings for walls, ceilings, and the like, all of which are intended to be comprehended Within the generic term walls.

The primary objects of the invention, in general, are to provide an acoustical construction which may be either manufactured in unit form or built up at the time of installation, and which embodies advantageous qualities of sound-absorption without using any great quantity of the usual sound-absorbing materials.

Another object of the invention is to provide a construction of the above indicated character .5 in which the exposed surface presents a smooth and pleasing appearance, which may be freely painted or otherwise decorated and which is advantageous from a sanitary standpoint.

These objects are obtained by covering the wall 10 surfaces which are to be acoustically treated with a membrane which is substantialy impervious or impedient to the passage of air, in spaced relation to the normally exposed wall surfaces, so that an air space of substantial thickness is confined J behind the membrane. It has been found that a high degree of sound-absorption will be obtained with this construction without using any of the usual sound-absorbing materials, although the use of a small quantity of such materials is desira- D ble in certain cases.

The invention will be better understood, and other objects and advantages thereof will become apparent, from a consideration of the detailed description of certain preferred embodiments of the invention appearing hereinafter, taken in connection with the accompanying drawing, in

which:

Figure l is a fragmentary, transverse sectional view through a ceiling or other wall to which the present invention has been applied in preformed units;

Fig. 2 is a perspective view, on a reduced scale. of one of the units used in a construction such as that illustrated in Fig. 1, part of the unit being broken away for the purposes of clearer illustration; and

Fig. 3 is a fragmentary, transverse sectional view of a wall to which the acoustical construction of the present invention has been applied in built-up form at the time of installation.

Referring first to Figs. 1 and 2 of the drawing, a portion of any ordinary wall II is shown with a plurality of preformed acoustical units secured to the normally exposed surface thereof. These 'units are of the form illustrated individually in Fig. 2, and are so constructed that the exposed surfaces thereof are constituted by flexible membranes which are substantially impervious or impedient to the passage of air, with an air space of substantial thickness confined behind said 5 membrane.

This arrangement is suitably provided by the construction illustrated, in which a rigid backing member I! is used as the base of each unit. This member may be made of any desired material, 10 such as wood, gypsum board, pressed board, corrugated paper board, cement-asbestos board, metal, cement or plaster slabs, tile, or any other material of suitable strength to support the remaining structure of each unit. The member I! is shown in Fig. l as consisting of a sheet of gypsum board having the usual paper coverings 12a of such board.

Each unit of this construction is built up by securing a marginal framework of spacing membars l3, III to one surface of the backing member l2. These spacing members may be of any desired material, such as those enumerated as being suitable for the backing member H, but in the construction illustrated they are shown as being of wood. They may be secured to the backing member by any suitable adhesive, by nailing, or in any other desired way.

Over the exposed edges of the spacing members l3 a flexible membrane I4 is secured. This membrane may be carried around the sides and part way around the back of each unit, as shown in Figs. 1 and 2, and may be secured in place either adhesively or otherwise. The only essential characterlstics of the membrane are that it either have sutlicient inherent flexibility or be so applied and so supported that it is sufliciently flexible to transmit a large portion of the sound impinging upon it, reflecting only a small portion; and that it be substantially impervious or impedient to the passage of air. It will be seen, therefore, that the membrane does not have to be of any particular material, but may be made of any one of numerous materials. Suitable examples are paper, cloth, metal foil, "cellophane", mica sheets, etc. Membranes of such materials may be readily painted, and since they are necessarily lmpedient to air in any event, the painting does not detract from their usefulness, as has been the case in many constructions heretofore used or proposed for acoustical purposes. A chip paper of .012" thickness has been found to be particularly suitable for a construction of proportions similar to those illustrated in Figs. 1 and 2.

In the unit form of construction shown in Fig. i, 5

the individual units may be secured to the normally exposed surfaces of the walls which are to be acoustically treated, in any suitable manner, as by nailing, cementing, or the like, so that the backing members I2 of the units become elements of the wall construction. The individual units may be made in any convenient size, from a size comparable to small tiles up to a large wallboard size or the like. v

The form of construction illustrated in Fig. 3 is of a type which may be readily built up at the time of installation. In this construction, a wall ll having a surfacing oi. wallboards l2 or the like, is provided with spacing members i3, 13 which are glued or otherwise suitably secured to the exposed surfaces of the wallboards. The membrane i4 is secured in place in front of the spacing members l3, l3 and is shown in this instance as being secured in place by moulding strips I5 nailed to the spacing members i3. This form of construction embodies a further modification in the application of sheets 16 of expanded metal or other foraminous reenforcing material behind the membranes ll. Such reenforcement may be used to good advantage to prevent the membrane sheets from being broken, torn or otherwise deformed and does not detract from the acoustical value of the installation as long as the membrane is left free to vibrate and the reenforcement has sufficient openings therein to offer little or no resistance to the passage of air or sound therethrough.

Fig. 3 also illustrates a further modification in the use of a small quantity of sound-absorbing material H which may be nailed, glued or otherwise secured to the exposed surfaces of the wallboards II, as shown. Such material may consist of felt or any other fibrous, porous or other material having sound-absorbing properties. The use of a thin layer of such material at the back of the confined air space behind the membrane i4 is of advantage in certain cases but is not an essential feature of the invention.

It will be seen from the foregoing that the essential characteristic of any construction embodying the present invention is the provision of a confined air space of substantial thickness behind a flexible membrane which is substantially impervious or impedient to the passage of air.

It has been found that such constructions provide a high degree of sound-absorption even without the use of any of the ordinary soundabsorbing materials. It is believed that this result is obtained by reason of the compression of the confined air behind the membrane, whereby the energy of the sound waves impinging upon the exposed surfaces of the membrances is converted into heat and dissipated as such. The compression of the air is caused by the vibration of the flexible membrance resulting from the impinging of sound waves thereon. The confined air acts as a damping means, whereby a large portion of the sound is converted into heat and thus absorbed.

This effect may be augmented, if desired, by the use of a small quantity of ordinary soundabsorbing material in the manner above described. The addition of such material in even slight quantities is highly effective in increasing the absorption of sound of certain frequencies, particularly in the higher ranges. As above indicated, however, the construction described is highly efficient without the use of any such material. The thickness or depth of the air space may be varied between relatively wide limits,

and it has been found that increasing the thickness of this space increases the sound absorption of the construction. As hereinbefore indicated, the present invention has to do with constructions in which an air space of substantial thickness is provided. By way of example, a space of the magnitude of one and one-half inches in thickness is advantageous, although this is not to be regarded as a limitation of such dimension. In any event, however, the thickness of sound-absorbing material at the back of such Space, when such material is used, is very slight in comparison with the total depth of the space, which is quite different from anything found in the prior art.

It should also be observed that the air space does not have to be absolutely confined. A marked, but lesser, degree of sound absorption can be obtained even when the membrane or other boundary of the air small and not too numerous perforations. This is explained by the fact that the pressure of the con fined air is not readily released by the retarded passage of air through such restricted openings in either direction. sential that the membrane be completely impervious to the passage of air, but only that it be substantially impervious or impedient thereto.

The sound-absorption characteristics of a construction made in accordance with this invention 5 can be varied by varying the flexibility of the membrane, as well as by varying the depth of the air space. It has also been found that a plurality of spaced membranes may be used to good advantage in some cases, different membranes may have different characteristics of flexibility, which affords further control over the peak absorption efliciency over the frequency range.

While only certain specific embodiments of the invention have been shown and described herein, it will be readily understood by those skilled in the art that various changes and modifications in the details of construction and arrangement may be made without departing scope of the invention, as set forth in the appended claims.

What is claimed as new and is desired to secure by Letters Patent, therefore, is:

1. An acoustical wall construction comprising a wall facing element of substantially non-soundabsorbent material, a flexible membrane substantially impervious to the passage of air, and means supporting said membrane in forwardly spaced,

parallel relation to said wall facing element to provide a confined air space of not substantially less than one inch therebetween.

2. An acoustical wall construction comprising a space is pierced with For this reason it is not esand in such cases the l 7 from the spirit and i rigid wall-surfacing board of substantially nonsound-absorbent material, substantially impervious to the passage of air, and means supporting said membrane in forwardly spaced, parallel relation to said wall-surfacing board to provide a confined air space of a flexible membrane not substantially less than one inch therebetween.

3. An acoustical wall construction comprising a gypsum board wall facing element, a paper membrane, and means supporting said membrane in forwardly spaced, parallel relation to said wall facing element to provide a. confined air space of not substantially less than about one inch therebetween.

4.An acoustical wall construction comprising a wall facing element of substantially non-soundabsorbent material, a flexible membrane substantially impervious to the passage of air, and means supporting said membrane in forwardly spaced, parallel relation to said wall facing elanent to provide a confined air space of not substantially less than one inch therebetween, the outer surface of said wall element being directly exposed to said air space.

5. An acoustical wall construction comprising a wall facing element of substantially non-soundabsorbent material, a flexible membrane substantially imperious to the passage of air, means supporting said membrane in forwardly spaced, parallel relation to said wall element to provide a confined air space of not substantially less than one inch therebetween, and a body of sound-absorbent material also disposed between said wall element and membrane, but, filling only a minor portion of the space therebetween.

6. An acoustical wall construction comprising a wall facing element of substantially non-scrunch absorbent material, a flexible membrane substantially impervious to the passage of air, means supporting said membrane in forwardly spaced, parallel relation to said wall element to provide a confined air space of not substantially less than one inch therebetween, and means for reenforcing said membrane.

7. An acoustical wall construction comprising a wall facing element of substantially non-soundabsorbent material, a flexible membrane substantially impervious to the passage of air, means supporting said membrane in forwardly spaced, parallel relation to said wall element to provide a confined air space of not substantially less than one inch therebetween, and a foraminous member behind said membrane for reenforoing the same.

8. An acoustical wall construction comprising a wall facing element of substantially non-soundabsorbent material, a flexible membrane substantially impervious to the passage of air, means supporting said membrane in forwardly spaced, parallel relation to said wall facing element to provide a confined air space of not substantially less than one inch therebetween, and a foramlnous metal sheet supported in position behind said membrane and in contact with the rear surface thereof over substantially its entire area, whereby said membrane is reenforced without destroying its sound-transmitting qualities.

9. An acoustical wall construction comprising a supporting wall and a plurality of acoustical units covering the surface thereof, each of said units comprising a rigid backing element of substantially non-sound-absorbent material, a flexible membrane substantially impervious to the passage of air, and means supporting said membrane in forwardly spaced, parallel relation to said backing element to provide a confined air space of not substantially less than one inch therebetween.

10. An acoustical wall construction comprising a rigid wall having a substantially non-soundabsorbent surface, a flexible membrane substantially impervious to the of air, and

means supporting said membrane in forwardly spaced, parallel relation to said wall surface to provide a. confined air space of at least one inch therebetween.

11. An acoustical wall construction comprising a wall facing element of substantially non-soundabsorbent material, a flexible celluiosic membrane substantially impervious to the passage of air, and means supporting said membrane in forwardly spaced, parallel relation to said wall facing element to provide a confined air space of not substantially less than one inch therebetween.

12. An acoustical wall construction comprising a wall facing element of substantially non-soundabsorbent material, an impervious metal foil membrane, and means for supporting said membrane in forwardly spaced, parallel relation to said wall facing element to provide a confined air space of not substantially less than one inch therebetween.

13. An acoustical wall construction comprising a wall facing element of substantially non-soundabsorbent material, a membrane of painte'd cloth substantially impervious to the passage of air, and means supporting said-membrane in forwardly spaced, parallel relation to said wall facing element to provide a confined air space of not substantially less than one inch therebetween.

. 14. An acoustical wall construction comprising a wall facing element of substantially nonsound-absorbent material, a flexible cellulosic membrane substantially impervious to the passage of air, means supporting said membrane in forwardly spaced, parallel relation to said well element to provide a confined air space of not substantially less than one inch therebetween, and a body of sound-absorbent material also disposed between said wall element and membrane, but filling only a minor portion of the space therebetween.

15. An acoustical wall construction comprising a wall facing element of substantially nonsound-absorbent material, a metal foil membrane substantially impervious to the passage of air, means supporting said membrane in forwardly spaced, parallel relation to said wall element to provide a confined air space of not substantially less than one inch therebetween, and a body of sound-absorbent material also disposed between said wall element and membrane, but filling only a minor portion of the space therebetween.

16. An acoustical wall construction comprising a wall facing element of substantially non-soundabsorbent material, a membrane of painted cloth substantially impervious to the passage of air, means supporting said membrane in forwardly spaced, parallel relation to said wall element to provide a confined air space of not substantially less than one inch therebetween, and a body of sound-absorbent material also disposed between said wall element and membrane, but filling only a minor portion of the space therebetween. CARLISLE K. ROOS. GEORGE D. KDTG.

CERTIFICATE OF CORRECTION.

Patent No. 2,045,315. June 23, 1936.

cARLisLE K. ROOS, ET AL.

It is hereby certified tha"t error appears in the printed specification of the above numbered patent requiririg correction as follows: Page 3, first column, line 12, claim 5, for "imperious" read impervious; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 11th dav of August. A. D. 1936.

Henry Van Arsdale ISeal) Actinz Commissioner of Patents. 

